Intermittent fault in the hall effect module (distributor)?

Maybe a current load heats up the fuel pump relay causing it to fail then
recover when it cools.

Differential fuel pressure switch on the front of the fuel distributor can be
intermittent.

Vacuum leaks?

Clogged fuel filter?

wrote:
> My 89 Audi 90 quattro has this strange problem. It starts right up and
> runs strong for about 25-30 min. Then it stalls out. Start it right
> back up and it will do it again. No matter how much you press the
> accelerator it will make its way to stall in a few seconds. the fuel
> pump does tane to make a louder buzz as it warms up. I feel that the
> pump is not the problem becasue I drove a CIS Jetta for 3 years that
> did the same thing. Any ideas.
>